Tobacco-related lung cancer is a leading cause of death among adults, and tobacco use accounts for -30% of cancer incidence and mortality. Therefore, eliminating tobacco uptake, increasing rates of tobacco cessation, and preventing smoking relapse are the cornerstones of cancer prevention. Moreover, a focus on groups disproportionately affected by tobacco use (e.g., minorities, low socioeconomic status (SES) groups, or populations at increased risk of relapse) is of clear importance in the fight against cancer. Previous research has shown that neighborhood-level SES is independently associated with higher smoking prevalence, but the role of the neighborhood in smoking outcome during a specific quit attempt has not been studied. The primary aim of this research is to examine how neighborhood characteristics influence the mechanisms underlying the process of smoking cessation and relapse prevention during a specific quit attempt among diverse community samples at increased risk for health disparities in cancer. Archival data will be examined from 4 study populations: Spanish speaking Hispanic smokers (n = 297), African-American smokers (n = 400), African-American, English speaking Hispanic, and Caucasian smokers in equal numbers (n = 420), and pregnant women who quit smoking and want to remain quit postpartum (n = 450). Specific aims of this project are to: i) Evaluate the relation between neighborhood characteristics (including neighborhood-level SES, racial/ethnic composition, neighborhood problems, vigilance, social cohesion, and social control) and smoking abstinence;2) Evaluate the relation of stress, depression, negative affect, self-efficacy, and social support with neighborhood characteristics and with smoking abstinence, respectively;and 3) Evaluate whether self-efficacy, depression, negative affect, stress, and/or social support mediate an observed association between neighborhood characteristics and abstinence. In a series of 4 studies, I will use multilevel modeling to examine the pathways through which the neighborhood context influences cessation using both questionnaire and ecological momentary assessment data, as well as sophisticated geographical software to map neighborhood-level demographic and economic data. These efforts will result in a better understanding of disparities in smoking status among underserved populations and provide information important for improving service to individuals from those communities, thereby affecting public health.